To View More...

Baseline plasma level of vitamic C is associated with significantly reduced risk of cataract in the participants in the Italian–American clinical trial of nutritional supplements and age–related cataract CTNS).

Baseline plasma level of vitamic C is associated with significantly reduced risk of cataract in the participants in the Italian–American clinical trial of nutritional supplements and age–related cataract CTNS).

You will receive an email whenever this article is corrected, updated, or cited in the literature. You can manage this and all other alerts in My Account

Abstract: :
Purpose:CTNS is designed to evaluate the safety and efficacyof a vitamin–mineral supplement in preventing age–relatedcataract or delaying its progression. At the randomization visitall participants received a complete ocular examination, photographicassessment of lens status, and measurement of the plasma levelof selected vitamins. We report here on the association betweenplasma levels of vitamins at baseline and presence and typeof cataract in CTNS participants.Methods: Plasma levels of vitamin C, vitamin A, vitamin E, beta–carotene,and red blood cells glutathione reductase activity (with andwithout added FAD) were measured on all participants at baselineand Folate and vitamin B12 levels were also assessed on a subset(20 %) of participants. Presence and severity of N, C, and PSCopacities were assessed using lens photographs according toa modification of the Wisconsin grading system. Data on a numberof variables were also collected by direct interview or measurement.We enrolled 1020 participants (55–75 yr) who, at the qualificationvisit, had "early cataract" (n= 710) or "no cataract" (n=310)according to study definitions.Results:Potential confounding variables that we found to beassociated with cataract (age, sex, diabetes, hypertension,alcohol use, smoking, family history of cataract) together withBMI and sunlight exposure index, were included in a final multiplelogistic model. We found a protective effect of high plasmalevels of vitamin C on any N cataract and on any cataract. Theadjusted ORs (upper vs lower quartile) were 0.56 (95% C.I. 0.35–0.91)for any cataract, and 0.47 (95% C.I. 0.27–0.80) for anyN cataract. The only other nutrient–related associationsof borderline significance noted in multivariate analyses werea protective effect on any cataract risk for persons in thehighest quartile of glutathione–reductase activity, andon PSC cataract risk for persons in the highest vitamin A quartile.Conclusions: This study suggests that higher plasma levels ofvitamin C (> 7.34 µg/ml) may be associated with a decreasedrisk of some types of age–related cataract. This findingmay have public health implications for the prevention of thiscommon disease.